Bikers who fantasise about roaring along the road astride the ultimate dream machine - a gleaming Harley-Davidson - may soon have their hopes dashed by an EC directive on noise restrictions, writes Jason Bennetto.

From next October, motorcycles over 175cc will have to reduce their noise level from 82 to 80 decibels. Manufacturers who have already muffled the exhaust systems of their air- cooled models say the only way to cut noise levels further is to use liquid-cooled engines.

Some - including Harley-Davidson - believe the addition of a radiator and cooling pipes will tarnish the image of their machines, and are threatening to withdraw from the European market. Martin Ginns, technical representative of Harley-Davidson UK, said: 'We would need to produce such a hideous exhaust system that would destroy the bike's image - it would be a disaster.'

The threat comes as Harley-Davidsons are enjoying a boom in Britain. UK sales have risen from about 50 a year in the early 1980s to 2,000 last year. For yuppie riders, known in the United States as RUBs - rich urban bikers - the appeal of nostalgia and style is a powerful attraction. Famous owners willing to pay up to pounds 12,000 for a bike include Peter de Savary, Arnold Schwarzenegger, Micky Rourke, and until recently Viscount Linley.